SYNTHETIC RESIN CURING AGENT

Some rubber base adhesives need vulcanization to produce adequate ultimate strength. The adhesion is mainly due to chemical interactions at the interface. Other rubber base adhesives (contact adhesives) do not necessarily need vulcanization but rather adequate formulation to produce adhesive joints, mainly with porous substrates. In this case, the mechanism of diffusion dominates their adhesion properties. Consequently, the properties of the elastomeric adhesives depend on both the variety of intrinsic properties in natural and synthetic elastomers, and the modifying additives which may be incorporated into the adhesive formulation (tackifiers, reinforcing resins, fillers, plasticizers, curing agents, etc.). 

It is an excellent agent for neutralizing the acidity which is developed by the high percentage af cloys used in rubber compounding, and thus reduces the curing time considerably. It is also used in the production of powerful synthetic detergents and in certain synthetic resins. 

Uses Mfg. of phenolic and thermosetting resins, furan polymers, urea-formaldehyde resins wetting agent foundry sand binders corrosion-resist, resins intermediate for esterification and etherification paints solvent, plasticizer for phenolic resins solvent for dyes and resins nonreactive epoxy resin diluent vise, reducer, cure promoter, and carrier in amine-cured epoxy resins gel retarder in casein/protein glues polymer sealants/cements synthetic flavoring agent in foods and pharmaceuticals cosmetics ingred. in food-pkg. adhesives... 

Diaminodiphenylmethane is an aromatic diamine used as a curing agent in epoxy resins of the bisphenol A type, as in the production of plastics, isocyanates, adhesives, elastomers, polyurethane (elastic and rigid foams, paints, lacquers, adhesives, binding agents, synthetics rubbers, and elastomeric fibers) and butyl rubber. Diaminodiphenylmethane is also a by-product of azo dyes. It is also possibly formed by hydrolysis of diphenylmethane-4,4 -diisocyanate. 

True properties are determined by the polymer and compound formulation and, for synthetic rubbers, additionally by type of curing agents such as sulfur or peroxides and the state of vulcanization. Typical properties for four polymers often used in automotive applications [acetals, nylons, polycarbonates, and unsaturated polyester (vinyl esters)] are shown in Tables 10.1 through 10.4. Typical property data is readily available from resin producers and compounders. Property data for elastomers is found in the chapter on elastomers in this handbook. 

Due to the high adhesion forces of the synthetic resins and the shrinkage of the cured components, the surfaces must be carefully prepared before the reinforcing material can be wound onto the core. The removal of resin residues and other contaminants can be done manually or with the aid of special cleaning machines for large mandrels. Subsequently, a release agent is applied. Adhesion can be reduced in order to facilitate later removal. Most of the release agent must be applied in several layers. They are then polished away and can be used for several production cycles. 

Use Curing catalyst and accelerator in resins and coatings, stabilizer, dispersion agent, lubricating and antistatic agent in synthetic fibers. 

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